Pyridinium Hydrobromide Perbromide

Moon, M. P.; Crouch, R. David

doi:10.1002/047084289x.rp292.pub2

Cited by 2 publications

(2 citation statements)

References 62 publications

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“…As anticipated, the regioselectivity of the bromination with PHP decreases in polar solvents (CH 3 OH/THF mixture) to match ratios seen using Br 2 in THF (∼1:1.4). Due to the poor solubility of PHP, 40 only THF, THF/CH 3 OH, and CH 2 Cl 2 were evaluated. In dichloromethane, PHP gave the best regioselectivity (1:6.6 C-4/C-5 3).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Substrate Controlled Regioselective Bromination of Acylated Pyrroles Using Tetrabutylammonium Tribromide (TBABr₃)

et al. 2018

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Electrophilic bromination of pyrroles bearing carbonyl substituents at C-2 typically results in a mixture of the 4- and 5-brominated species, generally favoring the 4-position. Herein, we describe a substrate-controlled regioselective bromination in which tetra-butyl ammonium tribromide (TBABr) reacts with pyrrole-2-carboxamide substrates to yield the 5-brominated species as the predominant (up to >10:1) product.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Substrate Controlled Regioselective Bromination of Acylated Pyrroles Using Tetrabutylammonium Tribromide (TBABr₃)

et al. 2018

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“…Bromination of 3 was previously accomplished by treatment with excess bromine (2.50 molar equiv) in the presence of pyridine (3.00 molar equiv) in methanol (8.00 relative volumes) at 25 °C. During the previous campaign, this process was run on a 2 kg scale (input 3 ) to deliver 4 in 55% overall yield across 11 batches.…”

Section: Resultsmentioning

confidence: 99%

Multikilogram-Scale Preparation of AZD4635 via C–H Borylation and Bromination: The Corrosion of Tantalum by a Bromine/Methanol Mixture

Douglas

Adams

Benson

et al. 2018

Org. Process Res. Dev.

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An efficient route to AZD4635 has been developed utilizing the Suzuki−Miyaura reaction of a boronate ester prepared by C−H borylation on a multikilogram scale. Preparation of the cross-coupling partner using bromine/pyridine/ methanol has highlighted the incompatibility of this reagent/solvent combination with tantalum, which is commonly used in the construction and repair of standard manufacturing vessels.

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Pyridinium Hydrobromide Perbromide

Cited by 2 publications

References 62 publications

Substrate Controlled Regioselective Bromination of Acylated Pyrroles Using Tetrabutylammonium Tribromide (TBABr₃)

Substrate Controlled Regioselective Bromination of Acylated Pyrroles Using Tetrabutylammonium Tribromide (TBABr₃)

Multikilogram-Scale Preparation of AZD4635 via C–H Borylation and Bromination: The Corrosion of Tantalum by a Bromine/Methanol Mixture

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Pyridinium Hydrobromide Perbromide

Cited by 2 publications

References 62 publications

Substrate Controlled Regioselective Bromination of Acylated Pyrroles Using Tetrabutylammonium Tribromide (TBABr3)

Substrate Controlled Regioselective Bromination of Acylated Pyrroles Using Tetrabutylammonium Tribromide (TBABr3)

Multikilogram-Scale Preparation of AZD4635 via C–H Borylation and Bromination: The Corrosion of Tantalum by a Bromine/Methanol Mixture

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Substrate Controlled Regioselective Bromination of Acylated Pyrroles Using Tetrabutylammonium Tribromide (TBABr₃)

Substrate Controlled Regioselective Bromination of Acylated Pyrroles Using Tetrabutylammonium Tribromide (TBABr₃)